JP2000241642A - Light transmit/receive module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce occupied ratio of excess case or package in a simple structure and attain downsizing and weight reduction by mounting all necessary elements (LD, PD, WDM, APM) to one platform. SOLUTION: An Si platform 110 is slightly higher at its front part and slightly lower at its rear part. A light wave guide 114 is placed at a high step portion in a central line shape. The front end of the light guide 114 is exposed to the front end surface of a substrate 110. The rear end of the light guide 114 is exposed to a side surface of the step portion. A receiving PD chip 115 is fixed over a position on the way to the light guide 114. At just back of it, a tilting groove 116 is drilled. A filter 117 is inserted into this tilting groove 116. Light propagated from a station through an optical fiber travels through the light guide 114, is reflected on the filter 117, and goes into and received by a light receiving element 115. While, transmitted light generated by an LD 123 permeates through the filter 117, and goes out from the light guide 114 to the optical fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bidirectional communication for transmitting information between a base station and a subscriber by passing optical signals of two or more different wavelengths through an optical fiber in one direction or two directions. The present invention relates to an optical transceiver module in which an element and a light emitting element are integrated. In particular, it is an object of the present invention to provide an optical transceiver module which has a simplified structure, is easy to manufacture, has excellent reliability, and is inexpensive.

[Description of Optical Bidirectional Communication] In recent years, the transmission loss of an optical fiber has been reduced, and the characteristics of a semiconductor laser (hereinafter abbreviated as LD) and a semiconductor light receiving element (hereinafter abbreviated as PD) have been improved. For this reason, it has become possible to transmit various information using light. It is called optical communication because it uses light. Light emitting elements for optical communication include LDs and LEDs, but for simplicity, those using LDs as light emitting elements will be described below. The light receiving element is P
There are D and APD, but the one using PD as a light receiving element will be described. The present invention can include any of the light emitting element and the light receiving element. The form of information to be transmitted is
There are telephone, facsimile, television image and so on. In particular, communications using long wavelength light such as light in the 1.3 μm band and light in the 1.55 μm band have been actively performed. Recently, a system capable of transmitting a signal bidirectionally using one optical fiber and simultaneously transmitting and receiving the signal has been studied. Since signals are transmitted in both directions, this is called two-way communication. The advantage of this method is that only one fiber is required.

FIG. 1 is a principle diagram of wavelength multiplexing bidirectional communication using light of different wavelengths among such bidirectional communication.
One station and a plurality of subscribers are connected by an optical fiber. Although only one subscriber is shown here, there are actually many subscribers. There are many branch points, and the optical fiber from the station is branched into many optical fibers to reach the subscriber's equipment.

The station amplifies a telephone or TV signal as a digital or analog signal, and drives the semiconductor laser LD1 with this signal. This signal enters the optical fiber 1 as a signal of the wavelength λ1. The light is guided to the intermediate optical fiber 3 by the splitter 2. This is the subscriber's splitter 4
As a result, the light enters the optical fiber 5 and is received by the light receiving element PD2. As a result, the signal is photoelectrically converted into an electric signal. The electric signal is amplified and signal-processed by a device on the subscriber side, and is reproduced as telephone sound or television image. The signal going from the base station to the subscriber side is called a downlink signal, and this direction is called a downlink system.

On the other hand, the subscriber converts a telephone or facsimile signal into an optical signal of wavelength λ2 by the semiconductor laser LD2. The light of λ2 enters the optical fiber 6 and is split by the splitter 4.
Is guided to the intermediate optical fiber 3 by the branching filter 2 on the station side.
And enters the light receiving element PD1. The station-side device photoelectrically converts the optical signal of λ2 by the PD1 and converts it into an electric signal.
This electric signal is sent to an exchange or a signal processing circuit to undergo appropriate processing. The direction in which a signal is sent to the station in this way is called an uplink system.

In the above description, λ1 is used only for the downstream system and λ2 is used only for the upstream system. In practice, however, light of the same wavelength may be used for both downstream and upstream. Occasionally, light of two wavelengths may be propagated upstream and downstream. In such a case, separation of the two types of light by wavelength becomes a very important problem.

[Explanation of optical demultiplexer] In order to use two wavelengths of light and perform two-way communication with a single optical fiber as described above, both the station side and the subscriber side use optical light. A function for identifying wavelengths and separating optical paths is required. The duplexers 2 and 4 in FIG. 1 perform the function. The demultiplexer combines the light of wavelengths λ1 and λ2 and introduces it into one optical fiber, or selects only one light from the light of two wavelengths and extracts it to one optical fiber. is there. A duplexer plays an extremely important role in performing wavelength multiplexing bidirectional communication.

At present, several types of duplexers have been proposed. This will be described with reference to FIGS. In the example of FIG.
The duplexer is made by an optical fiber or an optical waveguide.
The two light paths 8, 9 are adjacent in part 10, where the exchange of light energy takes place. Various couplings can be realized by the distance D and the distance L between the adjacent parts 10. Here, when light of λ1 is incident on the optical path 8, light of λ1 comes out on the optical path 11. When light of λ2 enters the optical path 12, light of λ2 comes out on the optical path 9.

FIG. 3 uses a multilayer mirror.
A dielectric multilayer mirror 15 is formed on the hypotenuse surfaces of the isosceles triangular glass blocks 13 and 14. By appropriately combining the refractive index and thickness of the dielectric, all the light of λ1 is transmitted,
The light of λ2 is all reflected. The dielectric is 45
It has the function of transmitting or reflecting light incident at an angle of degrees. This duplexer can also be used as the duplexers 2 and 4 in FIG. Such a demultiplexer is also called a demultiplexer / demultiplexer. WDM (wavelength division multiplexe)
Also called r). A duplexer using an optical fiber or a glass block is already commercially available.

[0010]

2. Description of the Related Art An optical transceiver module on the subscriber side will be described. In FIG. 4, the end of the optical fiber 16 laid from the station to the subscriber is terminated by an optical connector 17.
It is connected to an indoor optical fiber 18. The optical fiber WDM 21 is provided in the ONU module located inside the subscriber. The optical fiber 18 and the optical fiber 19 are wavelength-selectively coupled in the WDM. The LD module 25 is connected to the optical fiber 18 by the optical connector 22. The PD module 27 is connected to the optical fiber 19 via the optical connector 23.

The optical signal transmitted from the LD 25 to the optical fibers 24 and 18 is an upstream signal. The 1.3 μm band light transmits the subscriber's signal to the station. Optical fibers 19, 26 to P
The signal transmitted to the D module 27 is a downstream system. The PD module 27 receives the 1.55 μm signal from the station and performs photoelectric conversion. The LD 25 as a transmission device includes a circuit for amplifying and modulating a telephone or facsimile signal, a semiconductor laser for converting an electric signal to an optical signal, and the like. The PD module 27, which is a receiving device, receives a TV signal transmitted from a station,
Includes a photodiode for photoelectrically converting an optical signal from a telephone, an amplifier circuit, a demodulation circuit, and the like. WDM21 is 1.55
It has the function of separating light in the μm band and light in the 1.3 μm band. In this example, 1.3 μm is converted to 1.55 μm
Is used as downstream signal light.

The present invention relates to an improvement in an optical transmission / reception module when two-way communication is performed using optical signals of two different wavelengths. The optical transmission / reception module includes a light emitting element, a light receiving element, peripheral circuits thereof, and the like. Conventional technologies regarding these element technologies will be described.

[Description of Conventional Semiconductor Light Emitting Element (FIG. 5)] A conventional semiconductor light emitting element 25 will be described with reference to FIG. This is a semiconductor laser chip (LD) 29,
This is a module including a photodiode chip 30 for monitoring. The semiconductor laser chip 29 is fixed to the side surface of the ridge (pole) 31 of the header 32. This is because light is generated parallel to the plane of the chip. On the bottom of the header 32,
The photodiode chip 30 is fixed at a position where the back emission of the laser chip is incident. An appropriate number of lead pins 33 are provided on the lower surface of the header 32. The element mounting surface of the header 32 is covered with a cap 34.

A window 35 is opened at the center of the cap 34. The light of the semiconductor laser 29 exits vertically from the chip. A lens 37 is located immediately above the window 35. This is supported by the lens holder 36. Above the lens holder is a housing 38 on which a ferrule 39 is fixed. The ferrule 39 holds the tip of the optical fiber 40. The ends of the ferrule and the optical fiber are polished diagonally (8 degrees). This is to prevent return light from entering the semiconductor laser. The holder 36 is positioned with respect to the header 32 while monitoring the light of the semiconductor laser at the other end of the optical fiber 40. Further, the housing 38 is positioned with respect to the lens holder 36. Each electrode of the semiconductor laser chip 29 and the photodiode chip 30 is connected to one of the lead pins 33 by a wire.

The light emitted from the semiconductor laser is converged by a lens and enters the end of the optical fiber. Since the semiconductor laser is modulated by a signal, this light transmits the signal. The output of the semiconductor laser is monitored by a monitoring photodiode on the opposite side. 1.
The oscillation wavelength of 3 μm to 1.55 μm is determined by the material of the semiconductor layer.

[Description of Conventional Semiconductor Light Receiving Module (FIG. 6)] An example of a conventional semiconductor light receiving module will be described with reference to FIG. The light receiving element chip 41 is die-bonded to the upper surface of the header 42. Lead pins 43 are provided on the lower surface of the header 42. The top of the header 42 is the cap 4
4 covered. At the center of the cap 44 is an opening 45 for transmitting light. A cylindrical holder 46 is further fixed to the outside of the cap. This is for holding the lens 47.

Above the lens holder 46, a conical housing 48 is fixed. The tip of the optical fiber 50 is fixed by a ferrule 49, and the ferrule 49 is held by the housing 48. The ends of the ferrule 49 and the optical fiber 50 are obliquely polished.

In the case of the light receiving element, the position of the holder 46, the position of the housing 48, and the position of the ferrule 4 are monitored while passing the light through the optical fiber and monitoring the output of the light receiving element chip 41.
Determine the position of 9. The wavelength at which light can be received is determined by the semiconductor layer of the light receiving element. In the case of visible light, a Si light receiving element can be used. However, in the present invention, a Si photodiode is unsuitable because it is intended for a transmission / reception module using infrared light. In order to sense infrared light, InP having a narrower band gap is used as a substrate, and InGaAs or InG
It is necessary to use a compound semiconductor light-receiving element having a light-receiving layer such as aAsP.

[0019]

The problems of the prior art will be described. Subscribers are most common households. Therefore, optical two-way communication should have the same number of markets as the currently popular telephones. But ordinary households will not buy it unless it is as cheap as a regular metal phone. Inexpensive subscriber-side equipment is a condition for popularization. However, the combination of the individual modules (LD module, PD module, WDM module) according to the conventional example in FIG. The sum of the prices of these three individual modules is the price of the entire module, which is expensive.

The high price of such equipment has hindered the development of the optical subscriber system. Equipment must be reduced in cost for further progress. Attempts have been made to reduce the number of parts, make it more compact, and lower the cost. Some proposals have been made to reduce the cost of the optical transceiver module.

[A. Beam space separation type module (WD
M, PD, LD built-in receptacle type)] Masahiro Okunusu, Tasuko Tomioka, Shigeru Oshima "Receptacle type bidirectional wavelength multiplexing optical module" proposed by the 1996 IEICE Electronics Society Conference C-208, P208. FIG. 7 shows the outline. A WDM filter 61 is attached at an angle of 45 degrees inside a rectangular parallelepiped housing 60, and drum lenses 62, 63, and 64 are fixed to three walls. A PD 66 is attached to the end of the lens 62. An LD 68 is fixed at the end of the lens 63. The lens 64 serves as a connection end to the external optical fiber 69.

Actually, the housing 60 and the receptacle to which the optical fiber is fixed are detachable. The optical fiber 69 can be inserted into and removed from the housing. Therefore, the optical fiber 69 connected to the outside is detachably fixed to the housing 60. An optical fiber 69 from the outside is coupled to the PD 66 and the LD 68 by the lens 64 and the WDM 61. Light emitted from the optical fiber propagates through the space in the receptacle and spreads. Therefore, the light is condensed by the lenses 64, 62, and 63 to prevent the power from being spread. LD is 1.3μ
emits m light. This is transmitted through the WDM 61 obliquely, enters the optical fiber 69 via the lens 64, and becomes transmission light.

The received light propagating through the optical fiber 69 is 1.55 μm light, reflected by the WDM 61 and
After that, the light enters the PD 66 via 2. The WDM filter 61 has wavelength selectivity. It is much more compact than that of FIG. However, the LD and PD use independent elements and require three condenser lenses. And WDM
61 is required. Axis alignment is difficult. Although the size is reduced, the cost is almost the same as that of FIG.

[B. Y-branch optical waveguide module (Fig. 8)] Naoto Uchida, Yasufumi Yamada, Yoshinori Hib
ino, Yasuhiro Suzuki & Noboru Ishihara, "Low-cost
Hybrid WDM Module Consisting of a Spot-size Conver
ter Integrated Laser Diode and a Waveguide Photodi
ode on a PLC Platform for Access Network Systems ",
IEICE TRANS. ELECTRON., VOL.E80-C, NO.1, p88, JAN
Proposed by UARY 1997. This will be described with reference to FIG. A quartz-based transparent optical waveguide portion 71 is provided on a ceramic substrate 70. Optical waveguide 71
Is a stepped portion 72 cut out. By doping impurities, narrow waveguides 73, 74, 76, 77 and 78 branched in the Y direction are formed in the optical waveguide portion 71.

This module has two Y branches.
A WDM filter 75 is embedded at the intersection of the first Y branch. WDM75 reflects 1.55 μm and 1.3 μm
There is a wavelength selecting action for transmitting m. Electrode patterns 79, 80, 81, 82 are deposited on the step 72. An LED or LD 83 having an electrode at the bottom is bonded to the electrode patterns 79 and 80 of the step 72. This is an edge emitting type LED or LD 83 emitting 1.3 μm. Light is emitted from the light emitting point 85 on the end face.

A PD 84 of an end face light receiving type for sensing 1.3 μm is bonded to the rear electrode patterns 81 and 82. Since this also has an electrode on the bottom surface, the trouble of wire bonding can be omitted. Since it is an end face light receiving type, it is new and difficult to produce. A familiar commercial PD (top light receiving type) cannot be used in time. Free space light 88 includes 1.3 μm and 1.55 μm. This enters the waveguide 74 and reaches the WDM filter 75. WDM7
The 1.55 μm is reflected by 5 and returns as free space light 87 from the optical waveguide 73. The 1.3 μm further proceeds and enters both Y-branch waveguides 77 and 78. LE
What reaches D or LD 83 is wasted light. PD8
The light entering 4 is detected as received light. The LED or LD 83 emits transmission light. This is 1.3 μm light, but passes through waveguide 78, WDM 75, waveguide 74,
It becomes free space light. The light is condensed by a condenser lens (not shown) and enters an optical fiber (not shown).

Here, WDM is provided only to eliminate 1.55 μm. After all, the biggest difficulty of this proposal is that it is difficult to manufacture a planar Y-branch waveguide. Making a straight waveguide is easy,
It is not easy to make a curved Y-branch waveguide in a quartz waveguide portion. Also, the signal light once exits into free space, but must be focused on the end of the optical fiber by a lens, and it is difficult to align the axes. The cost of parts such as lenses drives up prices. There is also a possibility that the ends of the optical fibers are directly joined to the waveguides 73 and 74 without forming a free space. However, there is no change in that it is difficult to manufacture since it must be adhered by aligning the axes. After all, this is not enough to make an optical transceiver module cheap.

[C. Upward reflection WDM module; FIG. 9] Tomoaki Uno, Toru Nishikawa, Masahiro Mitsuda, Motoji Higashimon, Yasushi Matsui "Surface Mounted LD / PD Integrated Module" 1997 IEICE Electronics Society Conference,
C-3-89p198 (1997). By mounting LD and PD on the same substrate, mass production and miniaturization are aimed at. This will be described with reference to FIG. V-grooves 91 are formed by linearly notching the Si substrate 90. An optical fiber 92 is inserted and fixed in the V groove 91. A deep oblique groove 93 is cut obliquely in the middle of the optical path of the optical fiber. A part of the optical fiber 92 is also cut. An optical fiber cut piece 94 separated from the optical fiber 92 is formed. The WDM filter 95 is inserted into the oblique groove 93 and fixed.
The PD 96 is attached above the WDM 95 so as to straddle the V groove. On the other hand, a step 97 is cut out behind the Si substrate 90, and the LD chip 98 is fixed here. LD9
8 emits 1.3 μm transmission light 99. This propagates outside through the optical fiber 92 and the WDM 95. 1.55 μm reception light 100 from the outside is reflected by the WDM 95 and received by the PD 96. This causes the optical path to branch upward.

The structure appears to be simple. However, it is difficult to embed and fix the optical fiber in a fixed position, align the optical fiber with the LD, and align the optical fiber with the PD to obtain sufficient sensitivity. Single mode fiber has a core diameter of 10 μm,
Since the clad diameter is 125 μm, it is necessary to cut out a thick clad to insert a WDM filter. Therefore, the loss between the optical fibers 94 and 92 increases due to the wide gap. Since the V-groove itself becomes deep and wide, the distance between the WDM 95 and the PD 96 is long. Light spreads and sensitivity decreases. Further, light from the LD 98 leaks at the gap and does not sufficiently enter the optical fiber 92, and the loss increases.

[0030]

An optical transmitting / receiving module according to the present invention comprises a platform (substrate), a light guide linearly provided at the center of the platform to guide light, and a light guide provided in the middle of the light guide. A filter that transmits a part of the light to be transmitted and reflects a part of the light, a photodiode (PD) fixed on the platform to sense the light reflected by the filter, and a light emission that emits a transmission light provided on an extension of the light guide. Element (LD, LED).
Further, there are two forms A and B in the coupling structure with the optical fiber.
In the form A, a V-groove is provided in the platform, and the optical fiber is fixed in the V-groove. The fiber end is integrated with the transceiver module. Become a pigtail type. The received light from the optical fiber travels along the light guide (optical waveguide), is reflected upward by the filter, and is detected by the PD. Configuration B provides a platform with a plurality of guide pins to allow mating with an optical connector having an optical fiber end. In the case of B, an optical fiber of the optical connector and an optical guide of the optical transmitting / receiving module face each other by inserting guide pins into an optical connector of an appropriate standard. It is a receptacle type. The received light propagating through the optical fiber of the optical connector is reflected upward by the filter from the light guide, and
D is detected. Transmission light generated by the light emitting elements (LD, LED) enters the optical waveguide, passes through the filter, and enters the optical fiber.

Unlike the structure of FIG. 9 in which an optical fiber having a diameter of 125 μm is immersed in a V-groove, the optical waveguide can be formed shallowly on the surface of the substrate (platform), so that the PD does not spread after the received light is reflected by the filter. to go into. The loss of received light is small. When fixing the optical fiber in the V groove,
The height of the optical fiber varies due to the depth error, and it takes time to align the LD. Since the present invention uses an optical waveguide having no height variation, the coupling between the LD and the optical waveguide is facilitated.
The light guide is a straight waveguide formed by doping impurities into a transparent material to increase the refractive index. It is formed on a part of the material and does not stick the optical fiber. So it can be shallow. When an optical fiber is attached as in the related art, the optical fiber becomes deeper than its radius. An inorganic glassy transparent material can be used as the light guide. It may be a transparent plastic material. The best is quartz (SiO ₂ ). Quartz has a low refractive index (n = 1.4
5), but the refractive index can be locally increased by doping with Ge or the like. Since it is a straight waveguide, a complicated process such as a double Y branch shown in FIG. 8 is not required. When quartz is used as the substrate, the whole need not be quartz (SiO ₂ ). It is also possible to form a quartz waveguide by oxidizing only the surface of the Si substrate to SiO ₂ or by sputtering SiO ₂ on the Si substrate.

The optical transmitting / receiving module of the present invention has λ1, λ
The main use is to selectively use two different wavelengths for transmission and reception. Since light of different wavelengths is used, simultaneous two-way communication is possible. In this case, a filter provided in the middle of the light guide reflects almost 100% of the light of one wavelength λ1 and transmits the other wavelength λ2 at a ratio of almost 100%.
That is, in this case, it is a WDM filter. However, more simply, the optical transceiver module of the present invention can be used even when a single wavelength (λ) is used for transmission and reception. In that case, the filter provided in the middle of the light guide can transmit and reflect light of the wavelength at a fixed ratio.

Since the ratio of reflection and transmission with respect to light of a certain wavelength is determined, the filter can be made of a dielectric multilayer having different refractive indexes. For example, a filter in which a dielectric multilayer film having an appropriate refractive index thickness is laminated on a glass substrate can be used as a filter. Alternatively, a dielectric multilayer film may be laminated on a transparent polymer material.

InP substrate, InGaAs as light receiving element
A light receiving layer or an InGaAsP light receiving layer can be used. In that case, the signal light is 1.3 μm and 1.55 μm.
Near infrared light such as m can be used. Accordingly, an InGaAsP-based semiconductor laser is used.

Alternatively, a Si-PD can be used as the light receiving element. In that case, 0.7 to 0.8 as signal light
μm visible light can be used. A GaAlAs-based semiconductor laser can be used. Of course, a front-illuminated type PD can also be used. A back-illuminated PD can also be used. It is also preferable to install an amplifier near the PD to amplify the photocurrent and then take it out of the module. In this case, a weak optical signal can be received, and it is hardly affected by external noise.

First, the case (B) of the guide pin detachable type (receptacle type) will be described. This is characterized in that the end face of the optical connector optical fiber is directly brought into close contact with the optical waveguide and coupled. It becomes a receptacle type. Guide pins align the optical connector with the waveguide of the module. The diameter, length, interval, and the like of the guide pins are determined so that they can be fitted to the optical connector. For example, the diameter, length, interval, and the like of the guide pins are determined so that the guide pins can be fitted to the MT connector or the mini MT connector. Next, the optical fiber V
The case of groove fixing (A) will be described. A V-groove is cut vertically in the substrate (platform), and the end of the fiber is directly fixed.
Since the fiber end is fixed, it becomes a pigtail type. Alignment with the optical connector at the time of attachment / detachment becomes unnecessary.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1 Guide Pin (Receptacle Type) Type (B)] An optical transceiver module according to an example of the present invention of a guide pin type will be described with reference to FIG. Here, a Si substrate whose photolithography technology or the like is mature is used as the platform 110. Of course, other than the Si substrate, a ceramic plate, a polymer plate, and a metal plate can also be used. An optical guide (optical waveguide) 114 is formed on the Si platform 110 in the longitudinal direction. Since Si itself is opaque, a transparent layer of SiO ₂ is formed on the Si substrate. Waveguide is transparent Si
It is formed by forming a portion having a high refractive index in a part of O ₂ . Since it is a straight waveguide, it can be easily manufactured with a high yield. Although a method of manufacturing a waveguide is known, an outline will be described below.

FIG. 11 is a partial sectional view of the light guide. S
part i board (platform) 110 the upper surface of the oxidized or by a SiO ₂ to sputtering, to form the SiO ₂ buffer layer 111 on the Si substrate. A high-refractive-index SiO ₂ layer 112 doped with Ge is deposited thereon by sputtering or CVD. Ge-SiO ₂ layer 112 only at the center of high refractive index portion using mask
Leave. This is further covered with a SiO ₂ cladding layer 113 having a low refractive index. The high refractive index SiO ₂ 112 becomes the optical waveguide. This is the light guide 114 in FIG. Since the light guide 114 has a higher refractive index than the surroundings, it guides light,
There is a waveguide effect. A light guide can be created near the surface. The depth from the surface of the light guide is about 5 μm to 40 μm. The light guide allows light to pass through very near the surface of the platform. It is not a curved Y-branch waveguide like the optical waveguides of FIGS. 8, 4 and 2. Therefore, the production is easy and the yield is high.

The Si platform 110 is slightly higher at the front and slightly lower at the rear. The optical waveguide 114 is centerlined at the high step. The front end of the light guide 114 is exposed on the front end surface of the substrate 110. Optical waveguide (light guide)
The rear end of 114 is exposed on the side surface of the step. Light guide 114
The receiving PD chip 115 is fixed above a certain position in the middle. Immediately behind it is a diagonal groove 116. The filter 117 is inserted into the oblique groove 116. The inclination angle θ of the filter with respect to the vertical is in the range of 10 degrees to 50 degrees. For example, θ = 30 degrees. The filter is made of a dielectric multilayer film. The substrate is a transparent glass or a polymer material. By alternately laminating two types of dielectric films having an appropriate refractive index and thickness on a substrate, selectivity of reflection and transmission or wavelength selectivity is provided. The received light traveling through the optical waveguide is reflected by the filter and enters the PD 115 upward. As the PD, an appropriate material is selected according to the wavelength of the received light. For example, a Si photodiode or an InGaAs-based photodiode, or I photodiode
An nGaAsP-based photodiode is used.

In the longitudinal direction of the substrate 110, two V-grooves 11
8 and 119 are provided by a cutting method, a mold forming method, and an etching method. The processing method of the groove and the step differs depending on the material of the substrate. In the case of a ceramic or plastic substrate, it can be produced by a mold. In the case of a metal substrate, it can be formed by cutting. In the case of a Si substrate, a structure can be formed by etching. The case where Si anisotropic etching is used will be briefly described. A resist is applied to the (001) Si substrate, masked and exposed, and a rectangular slot is formed in the resist to perform etching with an anisotropic etching solution. Then (±
1 ± 11) planes are formed, which become V-grooves. The inclination angle of the V groove is 54.7 degrees, and the included angle of the valley is 70.6 degrees. The guide pins 120 and 121 are fixed on the V-shaped grooves 118 and 119. The guide pin is a metal bar, a plastic bar, a ceramic bar, or the like. An adhesive can be used for fixing. FIG. 12 shows a longitudinal sectional view of the platform.
The guide pins 120 and 121 are fixed to the V grooves 118 and 119 by adhesives 126 and 127, respectively. The number, length, diameter, interval, and the like of the guide pins are determined according to the holes of the optical connector to which this module is to be attached and detached. If the optical connector has three or four holes, the number of guide pins is also three or four.

The guide pins 120 and 121 and the light guide 1
The relative positional relationship of 14 is important. When the guide pin is inserted into the hole of the optical connector, the optical fiber of the optical connector and the light guide 114 must be accurately opposed. Preferably, the guide pin and the light guide are parallel. However, the guide pin and the light guide need not be parallel. It is only necessary that the optical fiber of the optical connector and the optical guide coincide with each other at the end face.

A preamplifier (AMP) 122 is fixed to the upper surface of the platform 110. This is for amplifying the signal of the PD 115. AM of PD electrode by wire
Connected to the input terminal of P122. FIG.
3 is an enlarged cross-sectional view of the vicinity of FIG. In some cases, the spacer 137 is necessary because the received light propagating through the optical waveguide 114 is reflected obliquely upward by the filter 117 and enters the PD 115. The spacer 137 is a horseshoe-shaped jig, and
38. The PD 115 is fixed on the spacer 137. Since the filter 117 is tilted by θ with respect to the vertical direction, the received reflected light becomes a beam tilted upward by 2θ. The receiving light beam is separated from the waveguide and the adhesive 13
9 enters the gap 138 of the filled spacer 137.
Here the beam bends. The corners follow Snell's law. The beam that has traveled through the adhesive 139 reaches the bottom surface of the PD 115, where it is refracted and enters the interior. The light travels inside the PD 115 and reaches the light receiving unit 140 of the PD. FIG.
Is a cross-sectional plan view of the spacer 137. The reason that the PD is lifted by the spacer is that the beam needs to be bent to the light receiving section 140 at the center of the PD 115. The refractive index of the adhesive 139 is the same as the refractive index of the platform, or an intermediate value between the refractive index of the platform and the PD 115 (n = about 3.5). An adhesive having the same refractive index as that of PD can be selected. The problems of the filter tilt angle, the spacer height, and the length of the PD will be described later with reference to FIG.

The metallized pattern 13 is formed on the lower rear surface.
1 to 136 are printed. The LD 123 is attached to a portion corresponding to the rear end of the optical waveguide on the lower surface. LD is GaA
An lAs semiconductor laser can be used. Or InG
It may be an aAsP semiconductor laser. As the light emitting element, an LED can be used in addition to the LD. LD123
A monitor PD 124 is attached to the rear of the camera. These are bonded to the ground metallized surface. Metallization and AMP122, LD123, Monitor PD124
Are connected to metallized electrodes by wires. The LD 123 emits transmission light. The monitor PD 124 emits light to both, and monitors the intensity of the light emitted backward. The light emitted forward enters the optical waveguide 114 and propagates there. Go straight through the filter 117. The transmitted light enters the optical fiber of the optical connector (not shown in FIG. 10) from the front end.
The driving current of the LD 123 is supplied from the lead pin to the LD through metallization.

Light received from the optical connector is transmitted to the optical waveguide 11.
4 and is reflected upward by the filter 117. This enters the PD 115 and is photoelectrically converted. The filter has such a property that the transmission light of the LD is transmitted by 100% and the reception light is reflected by 100%. It is important to separate both signal lights because they are transmitted and received simultaneously. This is possible because the transmitted light and the received light have different wavelengths. In this case, the filter is a WDM having wavelength selectivity. For example, as shown in FIG. 4, the transmission light is set to 1.3 μm and the reception light is set to 1.55 μm. The opposite is possible, but the multilayer structure of the filter will be different.

The monitor PD monitors the light amount of the LD that emits the transmission light and keeps the output constant. It is necessary to make the rear light of the LD enter the sensitive area of the PD. If the surface of the PD is parallel to the surface of the substrate 110, some contrivance is required. A configuration for guiding monitor light to the PD will be described with reference to FIGS. FIG. 15 shows an example in which the stripe region (light emitting region) of the LD 123 is fixed to the platform 110 with the lower side. It is assumed that the back-illuminated type PD 124 is located behind the PD 124 and the light receiving section is located at the center of the upper surface of the chip. Groove 14
3 is provided between the LD 123 and the PD 124. Groove 1
43 has a different manufacturing method depending on the substrate material. In the case of a Si substrate, it can be manufactured by anisotropic etching of Si (001) crystal as in the case of the V groove of the guide pin. In that case, the inclination of the concave groove is 54.7 degrees. The PD is fixed such that the bottom surface of the PD is located just above the groove 143. Since the lateral width of the PD 124 is wider than the width of the concave groove 143, there is no problem in fixing the PD 124. The end surface of the concave groove 143 becomes the inclined surface 144. When a groove is formed by Si etching, the angle of the inclined surface is 5
4.7 degrees. Light emitted forward from the LD enters a light guide (optical waveguide) 114. The light behind the LD 123 is inclined surface 1
44, is reflected and incident on the bottom surface of the PD 124,
Through the PD 124, it reaches the upper sensing area 145. The photocurrent generated here is extracted from the electrode 146 to the outside. In this way, the light of the LD is reflected once, changed its direction, and is incident on the PD from the back surface.

FIG. 16 shows the LD stripes facing upward. Since the light height of the LD changes, the height of the LD on the platform is slightly changed. Front light from the LD directly enters the optical waveguide 114. The backlight is
The light impinges on the inclined surface 144 and is reflected and enters the PD 124. The reason why the rear light needs to be reflected by the concave groove 143 and the inclined surface 144 is that the PD 124 is fixed in parallel with the surface of the substrate 110. If the PD is fixed perpendicularly to the substrate surface such that the sensitive area faces the stripe of the LD, no groove is necessary. A pole (not shown) extending vertically to the platform 110 may be set up, and a front-illuminated PD may be attached to the side of the pole facing the LD.

The module of the present invention can be used for alternate two-way communication (alternate transmission, ping-pong transmission) in addition to simultaneous two-way communication. Because the time is different, there is no need to use two different wavelengths of light. Same wavelength (λ) for both transmitted and received light
When light is used, transmission and reception are repeated at different times (alternately). For example, transmitting 1.3 μm,
1.3 μm is received. In that case, the filter 117 transmits and reflects the light of the wavelength at a certain ratio. For example, a function similar to that of a beam splitter that separates incident light at an angle θ such that transmission: reflection = 1: 1 is given to the filter 117.

The metallized pattern of the device shown in FIG. 10 is connected to each pin of a lead frame (not shown) by wire bonding. After that, it is stored in the case. 17 and 18 show a state where the platform is housed in a case. The type of package is arbitrary. A ceramic package may be used. Here, the case of an inexpensive plastic mold package is shown. The platform attached to the lead frame is placed in a mold, and a fluid resin is injected and solidified. Only the tip of the lead frame and the tip of the guide pin protrude from the plastic case.

The transmission / reception module 147 thus produced
Is a package in which a plastic package 148 covers and holds a part of a platform, a part of a lead frame, and a part of a guide pin. Two guide pins 120 and 121 project forward of the module 147. This is for inserting into the hole of the optical connector. A plurality of lead pins project vertically from the rear bottom surface. The lead pins are provided with an appropriate arrangement. Here, the rear end is of a type in which a plurality of lines are arranged at equal intervals. DIP type may be used.
The lead frame is connected to the internal electrode pattern,
D, PD, monitor PD, etc.
Alternatively, it is a terminal for extracting a reception signal, an LD power signal, and the like.

The operation of the above configuration will be described. When the guide pin is inserted into the hole of the optical connector of the other party, the optical connector and this module are combined. At that time, the optical fiber of the optical connector just faces the light guide 114.
Light from a station that has propagated through the optical fiber is transmitted through the light guide 11.
4, the light is reflected by the filter 117, enters the light receiving element 115, and is received by the light receiving element 115.

On the other hand, the transmission light generated by the LD 123 passes through the filter 117 and exits from the light guide 114 to the optical fiber. As described above, since the optical transceiver module of the present invention has no optical fiber, it does not trail. The optical fiber is coupled to the optical fiber by being inserted into the optical connector by a guide pin.

FIG. 19 shows a state in which an optical connector is fitted to the optical transceiver module of the present invention mounted on a signal processing board. The signal processing board 150 includes a circuit for converting a signal to be transmitted into a form suitable for transmission, amplifying and reproducing a received signal, and the like. The optical transceiver module 147 of the present invention is soldered to the signal processing board 150. M
The optical connector 152 such as a T connector or a mini MT connector has a hole at a position corresponding to the guide pins 120 and 121, and an end portion (indicated by a broken line) of the optical fiber 151 is located at an intermediate position. . Optical connector 1
By inserting the guide pins 120 and 121 into the hole 52, the optical fiber 151 faces the light guide 114. Light of 1.55 μm is transmitted from the station side, enters the light guide 114, is reflected by the filter 117,
It is detected at 115.

The transmission light from the LD 123 enters the optical fiber 151 from the light guide 114 and is transmitted to the office. Such an optical transceiver module of the present invention does not have an optical fiber itself, but can be easily attached to and detached from an optical connector. FIG. 20 shows an example of this type, but with a slightly different platform metallization pattern. Drill V-grooves 118 and 119 in the front half and guide pins 120 and 1
21 are the same. A shallow optical waveguide 114 is formed vertically in the center direction. There is an oblique groove 116 in the middle of the optical waveguide 114. Here, a WDM filter is obliquely inserted. The substrate 110 has metallized patterns 160 to 16
5 is formed by printing or the like. At the end of the optical waveguide 114 is a metallization 164 for attaching an LD. Behind it is a metallization 161 for attaching a PD. Metallization 160 serves as a ground plane for AMP. Groove 1
Reference numeral 43 is located between the LD and the PD and guides the LD back light to the PD. Only the metallized wiring is different from that of FIG. The metallized wiring can be designed freely.

[Embodiment 2 (Pigtail Type) (A)]
In the case of the receptacle type (B) described above, it is important to align the optical fiber of the optical connector with the optical waveguide of the optical transceiver module. Guide pins ensure proper alignment of the module and optical connector. The following is the type A (pigtail type). The pigtail type does not directly attach / detach the module and the optical connector since the fiber end is attached to the module. FIG.
This type of optical transceiver module will be described with reference to FIGS. Figure 21 shows the device chip on the platform,
4 shows an arrangement of optical fibers. The vertically long Si substrate (platform) 166 has a slightly higher middle portion. Both sides are low. An optical waveguide 167 is provided in the vertical direction at the high intermediate portion. Such a structure is similar to that shown in FIG. Although a metallized pattern is formed on the surface, it is not shown here.

The semiconductor chip is fixed on the metallization. PD1 for receiving on the optical waveguide 167 passing through the center
68 is attached. An LD 169 for transmission is fixed to the lower substrate surface near the end of the optical waveguide 167. L
The light of D169 can enter the optical waveguide 167. The monitor PD1 is behind the LD 169.
70 is fixed. The light amount of the LD 169 is monitored by the PD 170. A filter 171 inclined upward so as to cross the optical waveguide 167 is provided immediately after the PD 168. The AMP 172 is fixed to the side of the PD 168.
This is for amplifying the photocurrent of the PD 168. The platform 166 is placed on a lead frame (not shown), and each lead frame is connected to an electrode pattern such as a PD or an LD by a wire. A deeper V-groove 173 and a shallow V-groove 174 are formed in a step portion in front of the platform 166. Core wire 1 of optical fiber 175
76 (cladding: 125 μm in diameter) is fixed to the shallow V-groove 174, and the covering portion (900 μm in diameter) is
3 is fixed by an adhesive. Transparent resin 177 is L
It is dropped between D169 and PD170. In order to guide the back light of the LD to the PD, a transparent adhesive 177 is required during this time. For example, a silicone adhesive is used. The transparent adhesive also fills the free space between the filter 171 and the PD 168. This example employs an inexpensive plastic package. Lead frame and platform 16
6 is placed in a mold, and the flowing adhesive 178 is filled and cured. The curing adhesive 178 has a function of mutually connecting the platform, the lead frame, and the optical fiber, and is a package. FIG. 22 is a cross-sectional view of a molded state. As the curing adhesive, for example, an epoxy resin is used.

Transmission light from the optical fiber 175 is transmitted through the optical waveguide 1.
67, reflected by the filter 171 and entering the PD 168. The received light turns into a photocurrent, which is preamplified by the AMP 172. The transmission light emitted from the LD 169 enters the optical waveguide 167, goes straight, and enters the optical fiber 175. Such an operation is the same as that of the first embodiment. FIG.
25 to 25 show the outer shape of the package of the second embodiment. It is a DIP type in which lead pins protrude at equal intervals on both sides of the plastic package 178. The front end has an end portion of the optical fiber 175. The other end of the optical fiber is connected to an optical connector. Attachment to and removal from another optical fiber is performed at the optical connector. Unlike Embodiment 1, the alignment of the optical waveguide and the optical fiber is not required.
So there is no such thing as a guide pin.

FIG. 26 is a plan view showing a metallized pattern of the platform 166 of the device shown in FIGS. The structure of the V-grooves 173 and 174 for fixing the optical fiber does not change. The optical waveguide 167 is formed shallow in the center vertical direction. The filter groove 180 is formed obliquely upward. Immediately before is the metallization 187 for the PD. On the rear surface, a metallization 186 for LD and a metallization 183 for monitor PD are formed. Metallizations 181, 182, 18 connected to upper electrode pads of LD or PD
4, 185, etc. are provided with good symmetry. [Optical path when filter reflected light enters the back surface of PD] FIG.
First, the difference between the conventional example and the present invention will be clarified. In FIG. 9 as well, the received light is reflected upward by the filter, and is incident on the back surface of the PD. It is common in that respect. In the conventional example shown in FIG. 9, an optical fiber having a diameter of 125 μm is embedded in a V-groove. Therefore, the V-groove must be wide and deep. The base angle of the V groove is 2φ. (00)
1) When forming (± 1 ± 11) grooves in the substrate, 2φ =
70.6 degrees. Let the radius of the optical fiber (cladding) be r
(For example, 2r = 125 μm). The difference (embedment depth) between the upper surface of the optical fiber and the substrate surface is f. Then, the depth g of the V groove is

G = r (1 + cosecφ) + f (1)

And the width w of the V-groove is

W = 2r (tanφ + secφ) + 2ftanφ (2)

Is as follows. The depth e from the surface to the optical path is

E = r + f (3)

Is as follows. For example, φ = 35 degrees, r = 62.5
μm, f = 60 μm, g = 170 μm, w = 3
20 μm and e = 122.5 μm. Since the PD straddles the groove, a width of w or more is required. Since a bonding margin is required, the size of the PD must be increased. PD
Installation is difficult. There are other problems. Since the optical path from the filter to the PD is long, the reflected reception light spreads, and the amount of light reaching the light receiving area of the PD decreases.

FIG. 27 shows a path in which the received light is reflected by the filter, passes through the space, reaches the back surface of the PD, and goes to the light receiving region of the PD. The refractive index of the optical waveguide is n ₂ , the refractive index of the space is n ₁ , and the refractive index of the PD is n ₀ . Although it is a space, a space is formed by the spacer, and the space is filled with a transparent adhesive. Its refractive index is equal to the waveguide or P
It is set to be equal to D or between the two.

The optical waveguide parallel to the surface is defined as the y-axis, and the direction perpendicular to the surface is defined as the x-axis. The origin O is set at the intersection of the filter 171 and the optical waveguide. The positive direction of y is the direction of the transmitted light. The received light JO propagates in the negative y direction and is obliquely reflected by the filter. This enters the space (space of the concave portion of the spacer: adhesive) from point K and enters the back surface of the PD from point L. The distance between the optical waveguide and the surface of the platform is d, and the distance from the surface is P
Let h be the distance to the D bottom, m be the height of the PD, and k be the length of the PD. The angle of inclination of the filter 171 with respect to the vertical line (x-axis) is defined as θ.

The extension of the bottom surface TU of the PD and the filter 171
Let G be the intersection with the extension of The upper surface of the PD 168 is defined as VQ. This PD is a back-illuminated type and has a light receiving region M in the center of the upper surface VQ. Although there is an electrode above the light receiving area, it is omitted in FIG. If the filter 171 is wide, the PD 168 and the filter may come into contact with each other. Therefore, it is necessary to design the GU length to be positive. However, even if the GU is negative, the problem of collision can be avoided if the width of the filter is made narrower and lower than the spacer height h.

The received light JO can be represented by x = 0. The light OK reflected by the filter at the origin makes an angle of 2θ with the x-axis. K point is (d, dcot2θ)
It is. The light refracted at the point K becomes a light ray that forms an angle of Φ with the surface. The angle between the light incident on the PD at point L and the bottom surface is Θ
And The vectors KL and LM are respectively KL (h, h
cotΦ) LM (m, mcotΘ). Angle θ,
Snell's law between Φ and Θ

N ₂ cos 2θ = n ₁ cos Φ = n ₀ cosΘ (4)

Holds. Since n ₀ , n ₁ , n ₂ , and θ are determined, Φ and Θ are determined. The coordinates of points K, L and M are respectively

K = (d, dcot2θ) (5) L = (d + h, dcot2θ + hcotΦ) (6) M = (d + h + m, dcot2θ + hcotΦ + mcotｃｏ) (7)

Is as follows. G point

G = (d + h, − (d + h) tan θ) (8)

Is as follows. It is assumed that the length of the PD chip 168 is k, and the final arrival point M of the beam is the middle point of the upper surface of the chip. This is the best condition for incidence on PD.
Then the coordinates of point U are

U = (d + h, dcot2θ + hcotΦ + mcotΘ− (k / 2)) (9)

Is as follows. By comparing the y-coordinates of G and U,

UG = dcot2θ + hcotΦ + mcotΘ− (k / 2) + (d + h) tan θ> 0 (10)

Then, even if the width of the filter is wide, it does not correspond to the PD chip. The condition that UG is positive gives a lower limit on the height h of the spacer 137.

(K / 2) -mcotΘ−d (cot2θ + tanθ) <h (cotΦ + tanθ) (11)

The optical path length E from the reflection by the filter to the incidence on the PD is:

E = n ₂ dcosec 2θ + n ₁ hcosec Φ + n ₀ mcosecΘ (12)

Is as follows. In the present invention as well as in the element of FIG. 9, if the inclination θ, the refractive indices n ₁ , n ₂ , n ₀ , the chip thickness m, and the chip length k are common, the differences are the spacer height h and the optical path of the optical path. Only depth d. In the case of the present invention, since it is an optical waveguide, d = about 5 μm to 40 μm (particularly 5
μm to about 20 μm). However, in the case of FIG. 9, d = 120 μm or more. Therefore, a large difference appears in the first term of E. In FIG. 9, the light path length E is too long and the received light spreads, so that the amount of light entering the light receiving area of the PD is small.
In the present invention, since the first term of E is small, the beam does not spread, the amount of light entering the light receiving region is large, and the sensitivity is increased.

[0082]

(1) The optical transceiver module of the present invention has a simple structure. A conventional module as shown in FIG. 4 in which individual elements such as the WDM module in FIGS. 2 and 3, the LD module in FIG. 5, and the PD module in FIG. 6 are connected by an optical fiber has a complicated structure, is large, and is bulky. . Although the PD and LD are integrated in the module shown in FIG. 7, the PD and LD need to have a large volume because they propagate in space instead of an optical waveguide. Since light spreads due to spatial propagation, a lens is required.

The superiority of the present invention can be easily understood by comparing them. In the module of the present invention, WDM, PD, and LD are collectively surface-mounted on one substrate. In both the first and second embodiments, all necessary elements (LD, PD, WDM, AMP) are mounted on one platform. The structure is significantly simplified. As shown in FIG. 4, there is no need to connect PD, LD, and WDM with an optical fiber or an optical connector. The structure is simple and the proportion of extra cases and packages is small. Therefore, it becomes small and lightweight.
Since the elements are provided directly adjacent to each other, the reliability is high. It is not only light and small, but also inexpensive. It can be a driving force for widespread use of optical communication in ordinary households.

(2) Since the AMP can be provided close to the PD, external noise can be suppressed.

(3) A linear optical waveguide is provided on the substrate surface, and both transmission light and reception light pass through the same optical waveguide. Although the optical waveguide shown in FIG. 8 is provided on the substrate, it is a curved optical waveguide and is difficult to manufacture. Since the present invention requires only a straight optical waveguide, it is easy to manufacture and the yield is high. In the PLC technology, the current trend is to provide the optical waveguide with a WDM function, a Y-branch function, and the like so as to enhance the function as much as possible. The present invention does not take such a path. Rather, a simple, straight waveguide is placed on the substrate (platform).
Just make a book.

(4) The received light propagating through the shallow optical waveguide is reflected upward by the upward filter and is incident on the PD. Since the optical path from the reflection to the PD is short and the beam does not spread, the loss is small. The conventional example of FIG.
The filter is inserted obliquely upward into the optical fiber optical path, and the received light is reflected upward and incident on the PD. The present invention is similar to that of FIG. 9 in that it is an upward filter. But in fact it is very different. The module in FIG. 9 is 125 μmφ
A thick fiber is embedded in the substrate surface, the optical fiber is cut, and a filter is inserted diagonally. Filters have to be large. The optical path from the filter to the PD is long. The light spreads because the optical path is long and a condensing lens cannot be inserted. So the loss increases. In the case of the present invention, since the optical waveguide is shallow, the optical path length from filter reflection to PD incidence is short. Since the light does not spread, the loss is reduced. This is an important advantage.

In the conventional example shown in FIG. 9, the optical fiber must be completely embedded in the V-groove. The optical fiber must be fixed with an adhesive by cutting a deep groove. 125μmφ
In order to completely embed the fiber under the surface, the width of the V-groove at the surface becomes 250 μm to 300 μm. Since the depth of the V-groove is so deep, the filter groove must be cut deep and a wide filter must be inserted. The PD is fixed so as to straddle the V-groove. However, the V-groove is too wide, and disadvantages such as a reduction in the soldering area of the PD chip and conversely requiring a larger PD chip are caused. For example, assuming that the width of the V-groove is 300 μm, a bonding margin of only 50 μm can be obtained on both sides even with a 400 μm square PD. This cannot be reassured. If a large PD of 600 μm square is used, the bonding margin can be reduced to 150 μm. But this makes the PD too big. In addition, there is a disadvantage that the received light spreads from being reflected by the filter to entering the PD, so that only a small amount of light enters the PD.

The present invention forms a shallow optical waveguide on a substrate.
Since there is no groove, bonding of the PD is easy. No large PD is required. 5 from light guide layer to platform surface
It is about μm to 40 μm. The optical path from the reflection to the PD to the PD is short. Optical coupling with PD is possible in a short space where there is no room for the beam to spread. High coupling efficiency. (5) Further, there is no need to work after fixing the optical fiber in the groove. The filter groove may also be narrow. Since the light guide is shallow, it is only necessary to diagonally make a shallow cut in the substrate. A narrow filter is sufficient.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating wavelength multiplexing bidirectional communication.

FIG. 2 is a schematic diagram of an optical coupler or a WDM filter using an optical waveguide or an optical fiber.

FIG. 3 is a schematic diagram of an optical coupler or a WDM in which a dielectric multilayer film is laminated on a diagonal surface of a square prism glass block.

FIG. 4 is a diagram showing a configuration example of an optical transmission / reception module on the subscriber side according to a conventional example.

FIG. 5 is a sectional view showing an example of a conventional semiconductor light emitting device (LD module).

FIG. 6 is a sectional view showing an example of a conventional semiconductor light receiving element (PD module).

FIG. 7 is a schematic configuration diagram of a receptacle-type wavelength multiplexing optical transmission / reception module according to a conventional example.

FIG. 8 is a schematic perspective view of a Y optical waveguide type optical transceiver module according to a conventional example.

FIG. 9 is a schematic sectional view of an optical transceiver module having an upward WDM according to a conventional example.

FIG. 10 is a perspective view of a platform of an optical transmission / reception module of a type which is attached to and detached from an optical connector by a guide pin according to the first embodiment of the present invention.

FIG. 11 is a cross-sectional view of an optical guide (optical waveguide) manufactured on a platform in the present invention.

FIG. 12 is a vertical cross-sectional view across the guide pins of the platform of the optical transceiver module according to the first embodiment of the present invention;

FIG. 13 is a partially enlarged longitudinal sectional view of a receiving PD and a filter of the platform of the optical transceiver module according to the first embodiment of the present invention.

FIG. 14 is a partial cross-sectional plan view showing a cross section of a PD spacer and a filter of the platform of the optical transceiver module according to the first embodiment of the present invention;

FIG. 15 is an optical transmission and reception module according to the first embodiment of the present invention.
Sectional drawing of the part of D.

FIG. 16 shows an optical transceiver module according to the first embodiment of the present invention, in which an LD fixed to a platform with a light-emitting portion (stripe) facing upward and a monitor P for monitoring the amount of light.
Sectional drawing of the part of D.

FIG. 17 is a plan view of a completed product in which the optical transceiver module according to the first embodiment of the present invention is housed in a package.

FIG. 18 is a front view of a completed product in which the optical transceiver module according to the first embodiment of the present invention is housed in a package.

FIG. 19 is a plan view showing a state in which the optical transceiver module according to the first embodiment of the present invention is mounted on a board, and an MT connector is connected to the optical transceiver module.

FIG. 20 is a plan view of a platform of an optical transceiver module having another metallized pattern according to the first embodiment of the present invention.

FIG. 21 is a plan view showing the element arrangement of the platform of the optical transceiver module according to the second embodiment of the present invention.

FIG. 22 is a longitudinal sectional view of a state in which the platform of the optical transceiver module according to the second embodiment of the present invention is plastic-molded.

FIG. 23 is a plan view of a completed product in which the optical transceiver module according to the second embodiment of the present invention is accommodated in a package.

FIG. 24 is a front view of a completed product in which the optical transceiver module according to the second embodiment of the present invention is housed in a package.

FIG. 25 is a left side view of a completed product in which the optical transceiver module according to the second embodiment of the present invention is housed in a package.

FIG. 26 is a plan view of a platform having another metallization pattern of the optical transceiver module according to the second embodiment of the present invention.

FIG. 27 is a diagram illustrating a path through which received light reflected obliquely upward by a filter passes through a spacer space, enters the back surface of the PD, and reaches a sensitive region on the surface of the PD.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 optical fiber 2 splitter 3 optical fiber 4 splitter 5 optical fiber 6 optical fiber 7 optical fiber 8 optical path 9 optical path 10 proximity portion 11 optical path 12 optical path 13 glass block 14 glass block 15 dielectric multilayer film 16 optical fiber 17 light Connector 18 Optical fiber 19 Optical fiber 20 Proximity 21 WDM 22 Optical connector 23 Optical connector 24 Optical fiber 25 LD module 26 Optical fiber 27 PD module 29 LD chip 30 PD 31 Pole 32 Header 33 Pin 34 Cap 35 Window 36 Lens holder 37 Collection Optical lens 38 Housing (ferrule holder) 39 Ferrule 40 Optical fiber 41 Photodiode (PD) chip 42 Header 43 Pin 44 Cap 45 Window 46 Lens holder 47 Condenser lens 48 C Jing (ferrule holder) 49 ferrule 50 optical fiber 60 housing 61 WDM filter 62 to 64 drum lens 66 PD 68 LD 69 fiber 70 substrate 71 optical waveguide portion 72 step 73, 74 waveguide 75 WDM filter 76 to 78 waveguide 79 to 82 electrode pattern 83 LED or LD 84 PD 85 light emitting point 86 incident point 87 free space light 88 free space light 90 Si substrate 91 V groove 92 optical fiber 93 oblique groove 94 optical fiber cut section 95 WDM filter 96 PD 97 step section 98 LD 99 transmit light 100 incoming light 101 reflected reception light 110 platform (Si substrate) 111 SiO ₂ buffer layer 112 Ge-doped high refractive index SiO ₂ layer 113 SiO ₂ cladding layer 114 optical guide (optical waveguide: Ge dough High refractive index Si
(Remaining portion of O ₂ layer) 115 PD for reception 116 Diagonal groove 117 Filter 118 V groove 119 V groove 120 Guide pin 121 Guide pin 122 AMP (preamplifier) 123 LD 124 Monitor PD 126 Adhesive 127 Adhesive 131 to 136 Electrode 137 Spacer 138 Void 139 Transparent adhesive 140 Sensitive area 142 Groove 143 Groove 144 Inclined surface 145 Sensitive area 146 Electrode 147 Optical transceiver module 148 Mold resin 149 Lead pin 150 Printed circuit board 151 Fiber 152 Optical connector 160-165 Metallization pattern 166 (Si substrate) 167 Optical waveguide 168 PD 169 LD 170 PD (for monitor) 171 Filter 172 AMP 173 V groove 174 V groove 175 Optical fiber 176 Line 177 transparent resin 178 molded resin 179 lead pin 180 filter grooves 181-187 metallization

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04B 10/02 H04B 9/00 U (72) Inventor Miki Miki Kohara 1-chome, Shimaya, Konohana-ku, Osaka-shi, Osaka No. 3 Sumitomo Electric Industries, Ltd. Osaka Works F-term (reference) 2H037 AA01 BA02 BA11 CA39 DA03 DA04 DA11 DA12 2H038 AA22 BA25 CA45 CA74 2H047 KA04 LA18 MA05 MA07 PA04 PA05 PA21 PA24 QA04 RA00 TA05 TA23 TA31 TA43 2H048 GA01 GA04 GA24 GA26 GA62 5K002 AA05 AA07 BA02 BA07 BA13 BA14 BA21 BA31 DA02 DA04 FA01

Claims (16)

[Claims] 1. A substantially flat platform, an optical waveguide formed linearly on the platform and transmitting received light and transmitted light, a light receiving element provided immediately above the optical waveguide and sensing the received light, and a light receiving element. A filter that is provided in the vicinity of the optical waveguide and that is inclined obliquely upward and that receives the reflected light obliquely upward and introduces it into the light receiving element to transmit the transmitted light; and a light guide that is provided on the platform and on the extension of the optical waveguide. An optical transmission / reception module comprising a light emitting element (LD, LED) for transmitting transmission light to a wave path. 2. The optical transmission / reception module according to claim 1, wherein a groove is provided at an end of the platform, and an end of the optical fiber is fixed to the groove so that the center of the optical fiber faces the optical waveguide. 3. A groove is formed at an end of the platform to fix a guide pin, and the guide pin can be coupled to the optical connector by inserting the guide pin into a hole of the optical connector. The optical transceiver module according to claim 1, wherein the optical waveguides are opposed to each other. 4. The filter according to claim 1, wherein the filter is disposed so as to be inclined upward by about 30 degrees with respect to the optical waveguide.
4. The optical transceiver module according to any one of 3. 5. The transmission light (λ1) and the reception light (λ2) have different wavelengths and can perform two-way communication at the same time. The filter reflects the wavelength λ2 of the reception light by about 100% and the wavelength of the transmission light by about 1
The optical transceiver module according to claim 1, wherein the optical transceiver module is a wavelength-selective filter that transmits 00%. 6. The transmission light and the reception light have the same wavelength (λ), and the filter is a beam splitter that reflects a part of the reception light and transmits a part of the transmission light. The optical transceiver module according to claim 1. 7. The optical transceiver module according to claim 1, wherein the optical waveguide is a silica-based optical waveguide. 8. The optical transceiver module according to claim 1, wherein the optical waveguide is an optical waveguide made of a translucent polymer material. 9. The filter according to claim 1, wherein the filter is formed by forming an optical multilayer film on a translucent polymer thin film.
The optical transceiver module according to any one of the above. 10. The filter according to claim 1, wherein the filter is formed by forming an optical multilayer film on a translucent glass substrate.
9. The optical transceiver module according to any one of 8. 11. The optical transceiver module according to claim 1, wherein the light receiving element is a Si photodiode, and the light emitting element is a GaAlAs semiconductor laser. 12. The light receiving element is made of InGaAs or IGaAs.
The optical transceiver module according to any one of claims 1 to 10, wherein the optical transceiver module comprises an nGaAsP-based photodiode, and the light emitting element is an InGaAsP semiconductor laser. 13. The optical transceiver module according to claim 3, wherein the pitch of the guide pins is such that the guide pins can be fitted with an MT connector or a mini MT connector. 14. The receiving photodiode as a light receiving element is a back-illuminated type.
The optical transceiver module according to any one of the above. 15. A light emitting element is a semiconductor laser, and a monitor photodiode is provided behind the semiconductor laser,
15. The monitor photodiode according to claim 1, wherein the light reflected by the slope formed at the end of the concave groove provided between the semiconductor laser and the photodiode is received by the monitor photodiode. Optical transmission and reception module. 16. The optical transceiver module according to claim 1, wherein an amplifier for amplifying a light receiving element signal is arranged near the receiving photodiode serving as a light receiving element.